1. Field of the Invention
The present invention relates to a technology for controlling a focusing state by an imaging device including a multifocal lens.
2. Description of the Related Art
In recent years, an imaging device using a multifocal lens having a plurality of focal points has been known. For example, Patent Literature 1 describes that a subject image is obtained by convolution processing in an imaging device including a multifocal lens. Also, Patent Literature 2 describes that an imaging signal is corrected with an inverse function based on a point spread function in an imaging device including a multifocal lens. Furthermore, in Patent Literatures 1 and 2, images with different focal lengths are obtained by using the imaging device including the multifocal lens, and an in-focus image is obtained by restoration processing.
Still further, Patent Literature 3 describes that a barcode is read in a short focus region provided to a center portion of a multifocal lens and normal picture taking is performed in a long focus region provided to a peripheral portion of the lens.
On the other hand, as described in Patent Literature 4, pictures of the same subject are taken by a plurality of camera modules with different focal lengths instead of using a multifocal lens, and a multifocal image as a whole is obtained.